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    <element id="ERNA_CommonStockPurchaseWarrantsMember" name="CommonStockPurchaseWarrantsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_TwoThousandTwentySixPublicOfferingMember" name="TwoThousandTwentySixPublicOfferingMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PreFundedWarrantMember" name="PreFundedWarrantMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_MilestoneWarrantsMember" name="MilestoneWarrantsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PIPEInvestorMember" name="PIPEInvestorMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_CommonWarrantsMember" name="CommonWarrantsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_TwoThousandTwentyFivePrivatePlacementMember" name="TwoThousandTwentyFivePrivatePlacementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_MarketCapContingentConsiderationMember" name="MarketCapContingentConsiderationMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_TwoThousandEighteenAcquisitionMember" name="TwoThousandEighteenAcquisitionMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_LeaseAgreementMember" name="LeaseAgreementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ResearchAndDevelopmentExpensesMember" name="ResearchAndDevelopmentExpensesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_GeneralAndAdministrativeExpensesMember" name="GeneralAndAdministrativeExpensesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PrefundedWarrantsMember" name="PrefundedWarrantsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PlacementAgencyAgreementMember" name="PlacementAgencyAgreementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_SecuritiesPurchaseAgreementMember" name="SecuritiesPurchaseAgreementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DecemberTwoThousandTwentyTwoWarrantsMember" name="DecemberTwoThousandTwentyTwoWarrantsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_FactorLAndCAgreementMember" name="FactorLAndCAgreementMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_FirstTwelveMonthsMember" name="FirstTwelveMonthsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_FirstNineMonthsMember" name="FirstNineMonthsMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RetirementPlan401KMember" name="RetirementPlan401KMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_MrCheringtonMember" name="MrCheringtonMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PromissoryNoteOneMember" name="PromissoryNoteOneMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PromissoryNoteTwoMember" name="PromissoryNoteTwoMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StudyFeesMember" name="StudyFeesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PayrollAndRelatedMember" name="PayrollAndRelatedMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ProfessionalFeesMember" name="ProfessionalFeesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_MSALicenseFeesMember" name="MSALicenseFeesMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_OtherMember" name="OtherMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StockBasedCompensationMember" name="StockBasedCompensationMember" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DueToRelatedPartyCurrent" name="DueToRelatedPartyCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ForwardSalesContractExpense" name="ForwardSalesContractExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StockIssuedDuringPeriodValueIssuanceOfCommonStockInExchangeOfWarrants" name="StockIssuedDuringPeriodValueIssuanceOfCommonStockInExchangeOfWarrants" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StockIssuedDuringPeriodSharesIssuanceOfCommonStockInExchangeOfConvertibleNotes" name="StockIssuedDuringPeriodSharesIssuanceOfCommonStockInExchangeOfConvertibleNotes" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PaymentOfStockIssuanceCosts" name="PaymentOfStockIssuanceCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RemeasurmentOfRightOfUseAssetAndLeaseLiability" name="RemeasurmentOfRightOfUseAssetAndLeaseLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DisclosureLiquidityAndCapitalResourcesAbstract" name="DisclosureLiquidityAndCapitalResourcesAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_LiquidityAndCapitalResourcesTextBlock" name="LiquidityAndCapitalResourcesTextBlock" nillable="true" xbrli:periodType="duration" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DisclosureOperatingLeasesAbstract" name="DisclosureOperatingLeasesAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_OperatingLeaseRightOfUseAssetsAndLiabilitiesTableTextBlock" name="OperatingLeaseRightOfUseAssetsAndLiabilitiesTableTextBlock" nillable="true" xbrli:periodType="duration" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ShareBasedPaymentArrangementOptionGrantsInPeriodTableTextBlock" name="ShareBasedPaymentArrangementOptionGrantsInPeriodTableTextBlock" nillable="true" xbrli:periodType="duration" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ScheduleOfStockholdersEquityNoteWarrantsOrRightsActivityTextBlock" name="ScheduleOfStockholdersEquityNoteWarrantsOrRightsActivityTextBlock" nillable="true" xbrli:periodType="duration" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StockholdersEquityPercentage" name="StockholdersEquityPercentage" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_NonCashContractAmount" name="NonCashContractAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ForwardSalesContractLiabilityAtFairValue" name="ForwardSalesContractLiabilityAtFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_StudyFees" name="StudyFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_AccruedLegalFeesAndRelatedCurrent" name="AccruedLegalFeesAndRelatedCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RemeasurmentOfRightOfUseAsset" name="RemeasurmentOfRightOfUseAsset" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RemeasurmentOfLeaseLiability" name="RemeasurmentOfLeaseLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PrincipalPaymentsOnOperatingLeaseLiabilities" name="PrincipalPaymentsOnOperatingLeaseLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_SubleaseTerminationPayment" name="SubleaseTerminationPayment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_LeaseTerminationPayment" name="LeaseTerminationPayment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RemeasurementOfLeaseLiability" name="RemeasurementOfLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ReducedOperatingLeaseRightOfUseAsset" name="ReducedOperatingLeaseRightOfUseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_CompensationRelatedCostsSharebasedPaymentsAbstract" name="CompensationRelatedCostsSharebasedPaymentsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_CompensationRelatedCostsSharebasedPaymentsTable" name="CompensationRelatedCostsSharebasedPaymentsTable" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" />
    <element id="ERNA_StatementOfIncomeLocationAxis" name="StatementOfIncomeLocationAxis" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" />
    <element id="ERNA_StatementOfIncomeLocationDomain" name="StatementOfIncomeLocationDomain" abstract="true" nillable="true" xbrli:periodType="duration" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ClassOfWarrantOrRightClassification" name="ClassOfWarrantOrRightClassification" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ClassOfWarrantOrRightGrantsInPeriod" name="ClassOfWarrantOrRightGrantsInPeriod" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ClassOfWarrantOrRightExchangedInPeriod" name="ClassOfWarrantOrRightExchangedInPeriod" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_PaymentWarrantsExercisePrice" name="PaymentWarrantsExercisePrice" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DiscountedPurchasePriceOfSharesAndLiability" name="DiscountedPurchasePriceOfSharesAndLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_NoticePeriodForCustomaryTerminationRights" name="NoticePeriodForCustomaryTerminationRights" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_ContingentConsiderationObligationExpireDate" name="ContingentConsiderationObligationExpireDate" nillable="true" xbrli:periodType="duration" type="xbrli:dateItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanDeferralPercentOfAnnualCompensationPercentage" name="DefinedContributionPlanDeferralPercentOfAnnualCompensationPercentage" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanDeferralPercentOfTheirPayOnPreTaxBasis" name="DefinedContributionPlanDeferralPercentOfTheirPayOnPreTaxBasis" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchOne" name="DefinedContributionPlanEmployerMatchingContributionPercentOfMatchOne" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanEmployeeContributionAtThresholdOne" name="DefinedContributionPlanEmployeeContributionAtThresholdOne" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" name="DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_DefinedContributionPlanEmployeeContributionAtThresholdTwo" name="DefinedContributionPlanEmployeeContributionAtThresholdTwo" nillable="true" xbrli:periodType="duration" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_RelatedPartyTransactionsTable" name="RelatedPartyTransactionsTable" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" />
    <element id="ERNA_DebtInstrumentAccruedInterestRate" name="DebtInstrumentAccruedInterestRate" nillable="true" xbrli:periodType="instant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" />
    <element id="ERNA_SegmentReportingTable" name="SegmentReportingTable" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" />
</schema>
