A tissue sealant is described that includes the reaction product of (a) a polyol having at least two groups capable of reacting with an alkoxy silane and (b) an alkoxy silane having the formula: (R1R2R3)&mdashSi&mdashCH2&mdashZ where (i) Z is an &mdashOH, &mdashSH, &mdashNCO, or &mdashNHR4 group, where R4 is hydrogen or an alkyl group and (ii) each R1, R2, and R3, independently, is H, an alkoxy group, an alkyl group, a heteroalkyl group other than an alkoxy group, an aryl group, or a heteroaryl group, with the proviso that at least two of R1, R2, and R3 are alkoxy groups. The tissue sealant is moisture-curable and biodegradable in a physiological environment.