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  <xs:element id="blln_ClinicalTrialSupportAndOtherServicesMember" abstract="true" name="ClinicalTrialSupportAndOtherServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_CommonStockWarrantsMember" abstract="true" name="CommonStockWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_WarrantsFairValueDisclosure" abstract="false" name="WarrantsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_TermLoanMember" abstract="true" name="TermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_MeasurementInputInterestRateMember" abstract="true" name="MeasurementInputInterestRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_MeasurementInputExpectedTerm2Member" abstract="true" name="MeasurementInputExpectedTerm2Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_RedeemableConvertiblePreferredStockWarrantsMember" abstract="true" name="RedeemableConvertiblePreferredStockWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_AccruedInventoryPurchasesCurrent" abstract="false" name="AccruedInventoryPurchasesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_AccruedFixedAssetPurchasesCurrent" abstract="false" name="AccruedFixedAssetPurchasesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_AccruedInformationTechnologyPurchasesCurrent" abstract="false" name="AccruedInformationTechnologyPurchasesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_AccruedLegalExpensesCurrent" abstract="false" name="AccruedLegalExpensesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_AccruedPhlebotomyExpensesCurrent" abstract="false" name="AccruedPhlebotomyExpensesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_AccruedClinicalExpensesCurrent" abstract="false" name="AccruedClinicalExpensesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_A2024NotesMember" abstract="true" name="A2024NotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="blln_DebtCovenantTrancheDomain" abstract="true" name="DebtCovenantTrancheDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DebtCovenantTrancheOneMember" abstract="true" name="DebtCovenantTrancheOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DebtCovenantTrancheTwoMember" abstract="true" name="DebtCovenantTrancheTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DebtCovenantTrancheThreeMember" abstract="true" name="DebtCovenantTrancheThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DebtCovenantTrancheFourMember" abstract="true" name="DebtCovenantTrancheFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DebtInstrumentRedemptionPeriodSixMember" abstract="true" name="DebtInstrumentRedemptionPeriodSixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_OberlandCapitalMember" abstract="true" name="OberlandCapitalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_A2021LSACommonStockWarrantsMember" abstract="true" name="A2021LSACommonStockWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_A2022LSACommonStockWarrantsMember" abstract="true" name="A2022LSACommonStockWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_LoansPayableCapitalAdvancesNumberOfTranches" abstract="false" name="LoansPayableCapitalAdvancesNumberOfTranches" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="blln_DebtInstrumentCovenantTrailingSixMonthWorldwideNetRevenueMinimum" abstract="false" name="DebtInstrumentCovenantTrailingSixMonthWorldwideNetRevenueMinimum" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_DebtInstrumentCovenantTrailingSixMonthGrossMarginMinimum" abstract="false" name="DebtInstrumentCovenantTrailingSixMonthGrossMarginMinimum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="blln_DebtInstrumentRedemptionPeriod" abstract="false" name="DebtInstrumentRedemptionPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="blln_DebtInstrumentRedemptionInternalRateOfReturnGenerated" abstract="false" name="DebtInstrumentRedemptionInternalRateOfReturnGenerated" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="blln_DebtInstrumentRevenueParticipationAgreementPercentOfQuarterlyNetRevenue" abstract="false" name="DebtInstrumentRevenueParticipationAgreementPercentOfQuarterlyNetRevenue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
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  <xs:element id="blln_DebtInstrumentRevenueParticipationAgreementPrincipalAmountOfNotes" abstract="false" name="DebtInstrumentRevenueParticipationAgreementPrincipalAmountOfNotes" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="blln_PaymentsOfLoanTerminationFees" abstract="false" name="PaymentsOfLoanTerminationFees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_ClassOfWarrantOrRightRightToReturnWarrantsToCompanyCashValue" abstract="false" name="ClassOfWarrantOrRightRightToReturnWarrantsToCompanyCashValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="blln_ClassOfWarrantOrRightSharesWarrantsIssuedDuringPeriod" abstract="false" name="ClassOfWarrantOrRightSharesWarrantsIssuedDuringPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="blln_LockUpAgreementNumberOfDays" abstract="false" name="LockUpAgreementNumberOfDays" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="blln_DebtInstrumentCovenantScheduleAxis" abstract="true" name="DebtInstrumentCovenantScheduleAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="blln_DebtInstrumentCovenantScheduleDomain" abstract="true" name="DebtInstrumentCovenantScheduleDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_Q12026Member" abstract="true" name="Q12026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_Q22026Member" abstract="true" name="Q22026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_Q32026Member" abstract="true" name="Q32026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_Q42026Member" abstract="true" name="Q42026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_ThereafterMember" abstract="true" name="ThereafterMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_The2018PlanMember" abstract="true" name="The2018PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_The2025ESPPMember" abstract="true" name="The2025ESPPMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="blln_CommonStockConvertibleNumberOfSharesConvertiblePerShare" abstract="false" name="CommonStockConvertibleNumberOfSharesConvertiblePerShare" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="blln_CommonStockConvertibleTerm" abstract="false" name="CommonStockConvertibleTerm" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="blln_CommonStockConvertibleTermDeathOrIncapacitation" abstract="false" name="CommonStockConvertibleTermDeathOrIncapacitation" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="blln_CommonStockConvertibleNonActiveBoardMemberTerm" abstract="false" name="CommonStockConvertibleNonActiveBoardMemberTerm" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="blln_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedPerParticipant" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedPerParticipant" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
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  <xs:element id="blln_StockOptionsAvailableForFutureGrantsMember" abstract="true" name="StockOptionsAvailableForFutureGrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_CostOfProductAndServiceSoldMember" abstract="true" name="CostOfProductAndServiceSoldMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_AntidilutiveSecuritiesWarrantsToPurchaseCommonStockMember" abstract="true" name="AntidilutiveSecuritiesWarrantsToPurchaseCommonStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_AntidilutiveSecuritiesWarrantsToPurchaseRedeemableConvertiblePreferredStockMember" abstract="true" name="AntidilutiveSecuritiesWarrantsToPurchaseRedeemableConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_AntidilutiveSecuritiesUnvestedEarlyExercisedOptionsMember" abstract="true" name="AntidilutiveSecuritiesUnvestedEarlyExercisedOptionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="blln_NancyJohnsonCommonStockTradingArrangementMember" abstract="true" name="NancyJohnsonCommonStockTradingArrangementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_NancyJohnsonStockOptionsTradingArrangementMember" abstract="true" name="NancyJohnsonStockOptionsTradingArrangementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_ShanRikuSakakibaraMember" abstract="true" name="ShanRikuSakakibaraMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_ShanRikuSakakibaraCommonStockTradingArrangementMember" abstract="true" name="ShanRikuSakakibaraCommonStockTradingArrangementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_ShanRikuSakakibaraStockOptionTradingArrangementMember" abstract="true" name="ShanRikuSakakibaraStockOptionTradingArrangementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_DavidTsaoMember" abstract="true" name="DavidTsaoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="blln_OguzhanAtayMember" abstract="true" name="OguzhanAtayMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
