Superabsorbent Polymer Network Degradable by a Human Urinary Enzyme

Abstract

Owing to its superior water absorption capacity, superabsorbent polymer (SAP) based on a poly (acrylic acid) network is extensively used in industrial products such as diapers, wound dressing, or surgical pads. However, because SAP does not degrade naturally, a massive amount of non-degradable waste is discarded daily, posing serious environmental problems. Considering that diapers are the most widely used end-product of SAP, we created one that is degradable by a human urinary enzyme. We chose three enzyme candidates, all of which have substrates that were modified with polymerizable groups to be examined for cleavable crosslinkers of SAP. We found that the urokinase-type plasminogen activator (uPA) substrate, end-modified with acrylamide groups at sufficient distances from the enzymatic cleavage site, can be successfully used as a cleavable crosslinker of SAP. The resulting SAP slowly degraded over several days in the aqueous solution containing uPA at a physiological concentration found in human urine and became shapeless in ~30 days.

Superabsorbent Polymer Sponge for Saliva Absorption Pad

“…[8][9][10][11][12] Even though synthetic SAP currently available in the markets are biocompatible and have no direct threat to human life, disposal of such non-degradable material waste is a source of various environmental problems. [13][14][15] Therefore, natural polymers-based SAPs have received significant attention as they are degradable via multiple mechanisms of action, including enzymatic reactions, microbial attack, and hydrolysis. [15][16][17][18][19] SAP based on natural polymers (e.g., cellulose, [20][21][22] chitosan, [23][24][25][26] starch, [27][28][29] and alginate) [30][31][32] are renewable, biodegradable, and non-toxic.…”

“…[13][14][15] Therefore, natural polymers-based SAPs have received significant attention as they are degradable via multiple mechanisms of action, including enzymatic reactions, microbial attack, and hydrolysis. [15][16][17][18][19] SAP based on natural polymers (e.g., cellulose, [20][21][22] chitosan, [23][24][25][26] starch, [27][28][29] and alginate) [30][31][32] are renewable, biodegradable, and non-toxic. However, the main challenge in the area of biodegradable SAP is to synthesize fully degradable SAP that would rapidly and reversibly absorb water and have good mechanical properties.…”

Oxidative Degradation of Thermosets Based on Thioketal Cleavable Linkages in Aqueous Environment

“…Several microorganisms like fungi, bacteria, and algae secrete lytic enzymes, which induce polymer degradation and mineralization into monomers, dimers, oligomers, and finally convert them into H 2 O, CO 2 , CH 4 , and N 2 . Whang et al introduced a superabsorbent polymer (SAP) based on a poly­(acrylic acid) network, which was degraded by human urinary enzymes. Thirunavukarasu et al used the lipase enzyme released from the Cryptococcus sp.…”