Example spatial transcriptomics techniques use “continuous” polony arrays on a customized gel surface for spatial barcoding. By screening polyacrylamide (PAA) gel fabrication conditions, polonies formed on a crosslinked PAA gel were shown to exhibit a continuous, homogenous DNA distribution, which is highly suited for tissue barcoding applications. Compared with widely used polonies formed in flow cells that utilize linear PAA gels, continuous polonies showed efficient DNA amplification and restriction digestion to generate capture oligo arrays, which have a significantly better spatial RNA capturing performance. In addition, the crosslinked PAA gel showed sufficient constraints on lateral RNA diffusion and provides better mechanical strength and stability for tissue mapping assays than a semifluidic linear PAA gel used by previous methods.