A method of determining a spatial pattern of abundance and/or expression, of one or more protein targets across multiple sites in a 2D sample, comprising: delivering a probe for each of one or more protein targets to multiple sites in the sample attached to a support, wherein each probe comprises a target-binding moiety capable of binding to the probe's corresponding protein target and an oligonucleotide tag having a sequence that identifies the probe's corresponding protein target or target-binding moiety; allowing each probe to bind to its corresponding protein target in the sample; delivering at least one adaptor to the multiple sites in the sample attached to the support, wherein the at least one adaptor specifically binds to the probe, wherein the adaptor comprises an oligonucleotide identity tag that hybridizes to the oligonucleotide tag; delivering an oligonucleotide address tag (724, 726) to each of the multiple sites in the sample attached to the support, wherein one or more microfluidic devices with addressing channels are used to perform delivery of the oligonucleotide address tag (724, 726); coupling the oligonucleotide address tag to the at least one adaptor bound to the probe bound to the protein target, thereby generating an adaptor/oligonucleotide address tag conjugate, wherein the oligonucleotide address tag sequence identifies the site to which the oligonucleotide address tag is delivered; eluting the adaptor/oligonucleotide address tag conjugate bound to the probe; analyzing the eluted adaptor/oligonucleotide address tag conjugate by sequencing, wherein the amount of a sequencing product indicates abundance and/or expression of each of the one or more protein targets, the sequencing product comprising all or a portion of the oligonucleotide address tag sequence and all or a portion of the oligonucleotide identity tag sequence; and determining a spatial pattern of abundance and/or expression of the one or more protein targets across the multiple sites in the sample based on the analysis. delivering a probe for each of one or more protein targets to multiple sites in the sample attached to a support, wherein each probe comprises a target-binding moiety capable of binding to the probe's corresponding protein target and an oligonucleotide tag having a sequence that identifies the probe's corresponding protein target or target-binding moiety; allowing each probe to bind to its corresponding protein target in the sample; delivering at least one adaptor to the multiple sites in the sample attached to the support, wherein the at least one adaptor specifically binds to the probe, wherein the adaptor comprises an oligonucleotide identity tag that hybridizes to the oligonucleotide tag; delivering an oligonucleotide address tag (724, 726) to each of the multiple sites in the sample attached to the support, wherein one or more microfluidic devices with addressing channels are used to perform delivery of the oligonucleotide address tag (724, 726); coupling the oligonucleotide address tag to the at least one adaptor bound to the probe bound to the protein target, thereby generating an adaptor/oligonucleotide address tag conjugate, wherein the oligonucleotide address tag sequence identifies the site to which the oligonucleotide address tag is delivered; eluting the adaptor/oligonucleotide address tag conjugate bound to the probe; analyzing the eluted adaptor/oligonucleotide address tag conjugate by sequencing, wherein the amount of a sequencing product indicates abundance and/or expression of each of the one or more protein targets, the sequencing product comprising all or a portion of the oligonucleotide address tag sequence and all or a portion of the oligonucleotide identity tag sequence; and determining a spatial pattern of abundance and/or expression of the one or more protein targets across the multiple sites in the sample based on the analysis.