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  <xsd:element name="LeasePaymentsApplicableFromNovember2027UntilExpirationMember" id="sngx_LeasePaymentsApplicableFromNovember2027UntilExpirationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockIssuanceCostsIncludedInAccountsPayableAndAccruedExpenses" id="sngx_StockIssuanceCostsIncludedInAccountsPayableAndAccruedExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="MilestonePaymentUponAttainmentOfApproval" id="sngx_MilestonePaymentUponAttainmentOfApproval" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PaymentOfRoyaltyAndMilestoneAmounts" id="sngx_PaymentOfRoyaltyAndMilestoneAmounts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ClassOfWarrantOrRightPercentageOfExistingWarrantSharesToNewWarrantShareIssues" id="sngx_ClassOfWarrantOrRightPercentageOfExistingWarrantSharesToNewWarrantShareIssues" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="WarrantIssuanceCostsFinancialAndLegalFees" id="sngx_WarrantIssuanceCostsFinancialAndLegalFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="WarrantsAndRightsIssuedShares" id="sngx_WarrantsAndRightsIssuedShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="WarrantModificationAndNewWarrantsMember" id="sngx_WarrantModificationAndNewWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EquityIncentivePlan2025Member" id="sngx_EquityIncentivePlan2025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockOptionPlansAndWarrantsToPurchaseCommonStockDetailsScheduleOfSharesAvailableForGrantUnder2025PlanTable" id="sngx_StockOptionPlansAndWarrantsToPurchaseCommonStockDetailsScheduleOfSharesAvailableForGrantUnder2025PlanTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockOptionPlansAndWarrantsToPurchaseCommonStockDetailsScheduleOfSharesAvailableForGrantUnder2025PlanLineItems" id="sngx_StockOptionPlansAndWarrantsToPurchaseCommonStockDetailsScheduleOfSharesAvailableForGrantUnder2025PlanLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ExercisePriceRange1.37To10.78Member" id="sngx_ExercisePriceRange1.37To10.78Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ExercisePriceRange129.60To640.80Member" id="sngx_ExercisePriceRange129.60To640.80Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ExercisePriceRange1776Member" id="sngx_ExercisePriceRange1776Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DeferredTaxAssetsIntangibleAndFixedAssets" id="sngx_DeferredTaxAssetsIntangibleAndFixedAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="CommonStockCapitalSharesReservedForFutureIssuanceAdditions" id="sngx_CommonStockCapitalSharesReservedForFutureIssuanceAdditions" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
</xsd:schema>
