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  <import namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" />

  <import namespace="http://xbrl.sec.gov/dei/2014-01-31" schemaLocation="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd" />

  <import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" />

  <import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" />

  <import namespace="http://fasb.org/us-types/2015-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2015/elts/us-types-2015-01-31.xsd" />

  <element name="DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_DocumentAndEntityInformationAbstract" />

  <element name="DisclosureOfLicenseCollaborativeAndEmploymentAgreementsAndCommitmentsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_DisclosureOfLicenseCollaborativeAndEmploymentAgreementsAndCommitmentsAbstract" />

  <element name="LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsTextBlock" />

  <element name="NoncontrollingInterestPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_NoncontrollingInterestPolicyTextBlock" />

  <element name="RisksAndUncertaintiesPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RisksAndUncertaintiesPolicyTextBlock" />

  <element name="StockBasedPaymentArrangementsPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockBasedPaymentArrangementsPolicyTextBlock" />

  <element name="DepositsAndOtherAssetsNoncurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_DepositsAndOtherAssetsNoncurrent" />

  <element name="WarrantLiabilities" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_WarrantLiabilities" />

  <element name="EstimatedUsefulLifeOfAssetTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_EstimatedUsefulLifeOfAssetTableTextBlock" />

  <element name="AccruedExpensesTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_AccruedExpensesTableTextBlock" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndWarrantsVestedAndExpectedToVestOutstandingAndExercisableTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndWarrantsVestedAndExpectedToVestOutstandingAndExercisableTableTextBlock" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestExercisableTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestExercisableTableTextBlock" />

  <element name="ScheduleOfEstimatedFairValueOfWarrantLiabilityTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ScheduleOfEstimatedFairValueOfWarrantLiabilityTableTextBlock" />

  <element name="DueForLicenseAgreementsTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_DueForLicenseAgreementsTableTextBlock" />

  <element name="OrganizationAndNatureOfOperationsAndBasisOfPresentationTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_OrganizationAndNatureOfOperationsAndBasisOfPresentationTable" />

  <element name="OrganizationAndNatureOfOperationsAndBasisOfPresentationLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OrganizationAndNatureOfOperationsAndBasisOfPresentationLineItems" />

  <element name="ManufacturingEquipmentMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ManufacturingEquipmentMember" />

  <element name="SummaryOfSignificantAccountingPoliciesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_SummaryOfSignificantAccountingPoliciesTable" />

  <element name="MoneyMarketAccountsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_MoneyMarketAccountsMember" />

  <element name="SummaryOfSignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_SummaryOfSignificantAccountingPoliciesLineItems" />

  <element name="BalanceSheetParentheticalAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_BalanceSheetParentheticalAbstract" />

  <element name="ScheduleOfOtherCurrentAssetsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_ScheduleOfOtherCurrentAssetsTable" />

  <element name="OtherCurrentAssetsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OtherCurrentAssetsLineItems" />

  <element name="PrepaidExpensesResearchAndDevelopment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_PrepaidExpensesResearchAndDevelopment" />

  <element name="PrepaidClinicalResearchOrganizations" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_PrepaidClinicalResearchOrganizations" />

  <element name="ComputerAndOfficeEquipmentMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ComputerAndOfficeEquipmentMember" />

  <element name="ScheduleOfAccruedExpensesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_ScheduleOfAccruedExpensesTable" />

  <element name="AccruedExpensesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_AccruedExpensesLineItems" />

  <element name="AccruedManufacturingCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_AccruedManufacturingCosts" />

  <element name="AccruedVendorPayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_AccruedVendorPayments" />

  <element name="AccruedMilestonePayable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_AccruedMilestonePayable" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionExercisePrice" />

  <element name="RangeOfExercisePrice009200Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RangeOfExercisePrice009200Member" />

  <element name="RangeOfExercisePrice201300Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RangeOfExercisePrice201300Member" />

  <element name="RangeOfExercisePrice301600Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RangeOfExercisePrice301600Member" />

  <element name="RangeOfExercisePrice009600Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RangeOfExercisePrice009600Member" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisesInPeriod" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisesInPeriod" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisesInPeriodWeightedAverageGrantDateFairValue" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisesInPeriodWeightedAverageGrantDateFairValue" />

  <element name="WarrantsExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_WarrantsExercisePrice" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsWarrantsExercisableNumber" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsWarrantsExercisableNumber" />

  <element name="StockPlan2001Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockPlan2001Member" />

  <element name="StockPlan2007Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockPlan2007Member" />

  <element name="StockPlan2010Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockPlan2010Member" />

  <element name="EmployeesAndDirectorsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_EmployeesAndDirectorsMember" />

  <element name="EmployeeMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_EmployeeMember" />

  <element name="ConsultantMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ConsultantMember" />

  <element name="GeneralAndAdministrativeExpensesAndResearchAndDevelopmentExpenseMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_GeneralAndAdministrativeExpensesAndResearchAndDevelopmentExpenseMember" />

  <element name="EpitopeMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_EpitopeMember" />

  <element name="StockPurchaseWarrantsAggreementsAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:dimensionItem" id="syn_StockPurchaseWarrantsAggreementsAxis" />

  <element name="StockPurchaseWarrantsAggreementsDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockPurchaseWarrantsAggreementsDomain" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue" />

  <element name="IssuanceOfWarrantsToPurchaseOfCommonStock" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_IssuanceOfWarrantsToPurchaseOfCommonStock" />

  <element name="WarrantsExercisePricePerShare" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_WarrantsExercisePricePerShare" />

  <element name="InvestmentWarrantsExpirationDate1" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_InvestmentWarrantsExpirationDate1" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardWarrantsVestedAndExpectedToVestOutstandingNumber" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardWarrantsVestedAndExpectedToVestOutstandingNumber" />

  <element name="StockholdersEquityTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_StockholdersEquityTable" />

  <element name="PrevAbrLlcMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_PrevAbrLlcMember" />

  <element name="CedarssinaiMedicalCenterMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_CedarssinaiMedicalCenterMember" />

  <element name="CommonStockClosingPricePerShare" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_CommonStockClosingPricePerShare" />

  <element name="SaleOfStockForChannelAgreementPricePerShare" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_SaleOfStockForChannelAgreementPricePerShare" />

  <element name="LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsAbstract" />

  <element name="LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsTable" />

  <element name="QuarterlyInstallmentsPaymentPeriodAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:dimensionItem" id="syn_QuarterlyInstallmentsPaymentPeriodAxis" />

  <element name="QuarterlyInstallmentsPaymentPeriodDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_QuarterlyInstallmentsPaymentPeriodDomain" />

  <element name="FirstYearMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_FirstYearMember" />

  <element name="SecondYearMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_SecondYearMember" />

  <element name="ThirdYearMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ThirdYearMember" />

  <element name="IndMilestoneEventMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_IndMilestoneEventMember" />

  <element name="ApprovalMilestoneEventMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ApprovalMilestoneEventMember" />

  <element name="FieldExpansionFeeMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_FieldExpansionFeeMember" />

  <element name="PhaseIClinicalTrialsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_PhaseIClinicalTrialsMember" />

  <element name="PhaseIiiClinicalTrialsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_PhaseIiiClinicalTrialsMember" />

  <element name="NdaSubmissionInUsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_NdaSubmissionInUsMember" />

  <element name="EuropeanMedicinesAgencyApprovalMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_EuropeanMedicinesAgencyApprovalMember" />

  <element name="RegulatoryApprovalInAsianCountryMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RegulatoryApprovalInAsianCountryMember" />

  <element name="AnnualPaymentEffectivePeriodAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:dimensionItem" id="syn_AnnualPaymentEffectivePeriodAxis" />

  <element name="AnnualPaymentEffectivePeriodDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_AnnualPaymentEffectivePeriodDomain" />

  <element name="December312014Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_December312014Member" />

  <element name="December312015Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_December312015Member" />

  <element name="OfficeSpaceInAnnArborMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OfficeSpaceInAnnArborMember" />

  <element name="OfficeSpaceInRockvilleMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OfficeSpaceInRockvilleMember" />

  <element name="IntrexonMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_IntrexonMember" />

  <element name="JeffreyRileyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_JeffreyRileyMember" />

  <element name="CEvanBallantyneMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_CEvanBallantyneMember" />

  <element name="MarkPimentelMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_MarkPimentelMember" />

  <element name="AgreementAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:dimensionItem" id="syn_AgreementAxis" />

  <element name="OperatingLeaseLeasingTerm" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OperatingLeaseLeasingTerm" />

  <element name="ResearchAgreementFixedFee" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_ResearchAgreementFixedFee" />

  <element name="MilestonePayment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_MilestonePayment" />

  <element name="AdditionalCashPaymentForLicenseAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_AdditionalCashPaymentForLicenseAgreement" />

  <element name="UnregisteredSharesIssuedToLicenseAgreement" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_UnregisteredSharesIssuedToLicenseAgreement" />

  <element name="AdditionalConsiderationPayable" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_AdditionalConsiderationPayable" />

  <element name="CommonStockOutstandingPercentage" type="num:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_CommonStockOutstandingPercentage" />

  <element name="ExchangePercentageOfUnregisteredCommonStock" type="num:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="syn_ExchangePercentageOfUnregisteredCommonStock" />

  <element name="ScheduleOfComponentOfIncomeTaxExpenseBenefitTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_ScheduleOfComponentOfIncomeTaxExpenseBenefitTable" />

  <element name="ComponentsOfIncomeTaxExpenseBenefitLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ComponentsOfIncomeTaxExpenseBenefitLineItems" />

  <element name="ScheduleOfDeferredTaxAssetsAndLiabilitiesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_ScheduleOfDeferredTaxAssetsAndLiabilitiesTable" />

  <element name="DeferredTaxAssetsAndLiabilitiesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_DeferredTaxAssetsAndLiabilitiesLineItems" />

  <element name="DeferredTaxAssetsStocksIssuedForServices" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_DeferredTaxAssetsStocksIssuedForServices" />

  <element name="DeferredTaxAssetsStockIssuedForAcquisitionOfProgram" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_DeferredTaxAssetsStockIssuedForAcquisitionOfProgram" />

  <element name="DeferredTaxAssetsStockIssuedForlicenseAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_DeferredTaxAssetsStockIssuedForlicenseAgreement" />

  <element name="IncomeTaxesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_IncomeTaxesTable" />

  <element name="OperatingLossForwardPeriodAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:dimensionItem" id="syn_OperatingLossForwardPeriodAxis" />

  <element name="OperatingLossForwardPeriodDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OperatingLossForwardPeriodDomain" />

  <element name="IncomeTaxLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_IncomeTaxLineItems" />

  <element name="OperatingLossCarryforwardsExpireDate" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OperatingLossCarryforwardsExpireDate" />

  <element name="StockIssuedDuringPeriodValuemilestonePayment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodValuemilestonePayment" />

  <element name="StockIssuedDuringPeriodSharesmilestonePayment" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodSharesmilestonePayment" />

  <element name="StockIssuedDuringPeriodValueForExclusiveChannelCollaborationAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodValueForExclusiveChannelCollaborationAgreement" />

  <element name="StockIssuedDuringPeriodSharesForExclusiveChannelCollaborationAgreement" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodSharesForExclusiveChannelCollaborationAgreement" />

  <element name="StockIssuedDuringPeriodValueLicenseAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodValueLicenseAgreement" />

  <element name="StockIssuedDuringPeriodSharesLicenseAgreement" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodSharesLicenseAgreement" />

  <element name="StockIssuedOfDuringPeriodValueNewIssues" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedOfDuringPeriodValueNewIssues" />

  <element name="IssuanceValueOfCommonStockUponExerciseOfWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_IssuanceValueOfCommonStockUponExerciseOfWarrants" />

  <element name="StockIssuedForMilestonePayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedForMilestonePayments" />

  <element name="IssueOfStockForExclusiveChannelCollaborationAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_IssueOfStockForExclusiveChannelCollaborationAgreement" />

  <element name="StockIssuedForLicenseAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_StockIssuedForLicenseAgreement" />

  <element name="ProvisionForUncollectibleNoteAndInterestReceivables" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_ProvisionForUncollectibleNoteAndInterestReceivables" />

  <element name="EquipmentImpairmentLoss" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_EquipmentImpairmentLoss" />

  <element name="IncreaseDecreaseInDepositsAndOtherAssets" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_IncreaseDecreaseInDepositsAndOtherAssets" />

  <element name="DirectOfferingCost" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_DirectOfferingCost" />

  <element name="ProceedsFromIssuanceOfCommonStockForStockOptionAndWarrantsExercises" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_ProceedsFromIssuanceOfCommonStockForStockOptionAndWarrantsExercises" />

  <element name="IssuanceOfCommonStockUponExerciseSharesOfWarrants" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_IssuanceOfCommonStockUponExerciseSharesOfWarrants" />

  <element name="StockIssuedDuringPeriodSharesCashLessWarrantExercises" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockIssuedDuringPeriodSharesCashLessWarrantExercises" />

  <element name="AccruedClinicalConsultingServices" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_AccruedClinicalConsultingServices" />

  <element name="StockWarrantsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockWarrantsMember" />

  <element name="IssuanceOfWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_IssuanceOfWarrants" />

  <element name="ScheduleOfWarrantActivityTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ScheduleOfWarrantActivityTableTextBlock" />

  <element name="ScheduleOfQuarterlyFinancialInformationTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="syn_ScheduleOfQuarterlyFinancialInformationTable" />

  <element name="ScheduleOfWarrantOutstandingAndExercisableTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ScheduleOfWarrantOutstandingAndExercisableTableTextBlock" />

  <element name="SelectedQuarterlyFinancialInformationLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_SelectedQuarterlyFinancialInformationLineItems" />

  <element name="OptionsToBeReceivedCommonStockShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_OptionsToBeReceivedCommonStockShares" />

  <element name="StockOptionsExpirationTerm" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockOptionsExpirationTerm" />

  <element name="ExercisePrice1Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ExercisePrice1Member" />

  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGrantDateFairValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGrantDateFairValue" />

  <element name="StockholdersEquityLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockholdersEquityLineItems" />

  <element name="AgreementDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_AgreementDomain" />

  <element name="ChannelCollaborationAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ChannelCollaborationAgreementMember" />

  <element name="StockPurchaseAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_StockPurchaseAgreementMember" />

  <element name="GrossProceedsFromIssuanceInitialPublicOffering" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_GrossProceedsFromIssuanceInitialPublicOffering" />

  <element name="BiomicsAndMarkPimentelMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_BiomicsAndMarkPimentelMember" />

  <element name="DrPimentelsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_DrPimentelsMember" />

  <element name="MilestonePaymentUponFirstDosing" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" xbrli:balance="debit" substitutionGroup="xbrli:item" id="syn_MilestonePaymentUponFirstDosing" />

  <element name="LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_LicenseCollaborativeAndEmploymentAgreementsAndCommitmentsLineItems" />

  <element name="RileyEmploymentAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_RileyEmploymentAgreementMember" />

  <element name="ShallcrossEmploymentAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ShallcrossEmploymentAgreementMember" />

  <element name="BallantyneEmploymentAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_BallantyneEmploymentAgreementMember" />

  <element name="ExercisePrice2Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ExercisePrice2Member" />

  <element name="ExercisePrice3Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ExercisePrice3Member" />

  <element name="ExercisePrice4Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ExercisePrice4Member" />

  <element name="ExercisePrice5Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="syn_ExercisePrice5Member" />

  <element name="OperatingAnnualLeasePayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" xbrli:balance="credit" substitutionGroup="xbrli:item" id="syn_OperatingAnnualLeasePayments" />
</schema>

