Table 4.

Strategies for small biomolecule detection using hydrogel-based glucose biosensors.

Hydrogel	Transduction Strategy	Specification	Reference
Polyaniline	Electrochemical	RT: 3 s; LR: 0.01–8 mM	[179]
Polyaniline–PEG	Electrochemical	-	[180]
PEG	Optical	RT: 10 min; LR: 0–600 mg/dL${}^{-1}$	[166]
PVA–vinyl pyridine	Electrochemical	RT: 11 s	[181]
Chitosan	Electrochemical	RT: 7 s; LR: 5 $\mathsf{\mu }$M to 2.5 nM	[182]
Chitosan–graphene oxide	Electrochemical	LR: 0.02–6.78 mM	[183]
Polypyrrole	Electrochemical	LR: up to 15 mM	[184]
PEG (injectable)	Optical	RT: 11 min; LR: up to 370 mg dL${}^{-1}$	[185]
Polyvinylpyrrolidone	Optical	-	[186]
Alginate	Optical	LR: 2.6–350 mg/dL${}^{-1}$	[187]
HEMA	Electrochemical	LR: 10 $\mathsf{\mu }$M to 40 mM	[188]

HEMA: Hydroxyethyl methacrylate; LR: Linear range; PEG: Polyethylene glycol; PVA: Poly(vinyl alcohol); RT: Response time [162].