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	  <link:usedOn>link:calculationLink</link:usedOn>
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    <element id="CLSN_DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingWithinThreeMonthsFairValue" name="DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingWithinThreeMonthsFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingBetweenThreeAndTwelveMonthsAmortizedCost" name="DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingBetweenThreeAndTwelveMonthsAmortizedCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingBetweenThreeAndTwelveMonthsFairValue" name="DebtSecuritiesAvailableforsaleMaturityAllocatedAndSingleMaturityDateRollingBetweenThreeAndTwelveMonthsFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleDebtSecuritiesAmortizedCostBasisCurrent" name="AvailableForSaleDebtSecuritiesAmortizedCostBasisCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleSecuritiesUnrealizedGainsFairValue" name="AvailableForSaleSecuritiesUnrealizedGainsFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleSecuritiesUnrealizedHoldingGainsLessThanTwelveMonths" name="AvailableForSaleSecuritiesUnrealizedHoldingGainsLessThanTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleSecuritiesUnrealizedLossFairValue" name="AvailableForSaleSecuritiesUnrealizedLossFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleSecuritiesUnrealizedHoldingLossesLessThanTwelveMonths" name="AvailableForSaleSecuritiesUnrealizedHoldingLossesLessThanTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AvailableForSaleSecuritiesUnrealizedHoldingGainsLossesLessThanTwelveMonths" name="AvailableForSaleSecuritiesUnrealizedHoldingGainsLossesLessThanTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_NoncashCharge" name="NoncashCharge" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_LongTermDebtMaturitiesRepaymentsOfPrincipalYearFourAndThereAfter" name="LongTermDebtMaturitiesRepaymentsOfPrincipalYearFourAndThereAfter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EarlyTerminationFee" name="EarlyTerminationFee" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EndOfTermCharges" name="EndOfTermCharges" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_FinalPaymentPercentage" name="FinalPaymentPercentage" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EndOfTermChargePercentage" name="EndOfTermChargePercentage" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_ClassOfWarrantOrRightWarrantsOrRightsCancelled" name="ClassOfWarrantOrRightWarrantsOrRightsCancelled" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EndOfTermFees" name="EndOfTermFees" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_ShelfRegistrationStatementAmount" name="ShelfRegistrationStatementAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_AggregateOfferingPrices" name="AggregateOfferingPrices" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_UnderwritingDiscountPricePerShare" name="UnderwritingDiscountPricePerShare" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_PercentageOfUnderwritingDiscountOnPublicOfferingPrice" name="PercentageOfUnderwritingDiscountOnPublicOfferingPrice" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_PlacementAgentFeeDescription" name="PlacementAgentFeeDescription" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_StockOptionsStrikePriceDescription" name="StockOptionsStrikePriceDescription" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EarnoutMilestoneLiability" name="EarnoutMilestoneLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_GainLossFromChangeInFairValueOfEarnOutMilestoneLiability" name="GainLossFromChangeInFairValueOfEarnOutMilestoneLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_RiskadjustmentAssessmentOfAchievingMilestone" name="RiskadjustmentAssessmentOfAchievingMilestone" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_DiscountRatesOnMileStoneLiabilities" name="DiscountRatesOnMileStoneLiabilities" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EstimatedTimeToAchieveMileStone" name="EstimatedTimeToAchieveMileStone" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EarnoutMilestoneLiability1" name="EarnoutMilestoneLiability1" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_NoncashChargeOnEarnoutMilestoneLiability" name="NoncashChargeOnEarnoutMilestoneLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_EarnoutPaymentOptionsDescription" name="EarnoutPaymentOptionsDescription" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingWeightedAverageExercisePrice" nillable="true" xbrli:periodType="instant" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExerciseInPeriodWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExerciseInPeriodWeightedAverageExercisePrice" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_SharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsOutstandingWeightedAverageRemainingContractualTerm2" name="SharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsOutstandingWeightedAverageRemainingContractualTerm2" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearThreeAndThereAfter" name="LesseeOperatingLeaseLiabilityPaymentsDueAfterYearThreeAndThereAfter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_DeferredRevenueAmortizationPeriod" name="DeferredRevenueAmortizationPeriod" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_UpfrontPaymentBeingRecognized" name="UpfrontPaymentBeingRecognized" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="CLSN_OperatingLeaseImputedInterest" name="OperatingLeaseImputedInterest" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
</schema>
