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This work addresses two main challenges in additive manufacturing of cellulosic hydrogels and cryogels. They are (1) the rheological properties of suspensions of electrosterically stabilized nanocrystalline cellulose (ENCC, a member of the family of hairy nanocelluloses) are inadequate for 3D printing of hydrogels and (2) 3D printed cellulose nanocrystal (CNC) cryogels have poor mechanical properties. The above limitations are effectively addressed by hybridization of CNC/ENCC in the presence of a salt at an optimized weight ratio. Controlling the CNC/ENCC weight ratio leads to high tunability of the rheological properties of the hybrid systems, resulting in high-fidelity printing of 3D hydrogels. Similarly, high tunability in the mechanical performance of the cryogels, obtained upon freeze drying of the printed hydrogels, is achieved by manipulating the CNC/ENCC ratio. Compared to neat CNC cryogels, the compressive strength of the CNC/ENCC (1:1) cryogels is 78% higher. Combined, CNC bestows high printability on the cryogels, while the presence of ENCC leads to the strengthening of the corresponding super porous solid materials. Our findings open new opportunities for sustainable, biocompatible, and lightweight cellulosic structured scaffolds that can be tailored for a broad spectrum of applications.

A multi-component hydrogel was developed using bacterial cellulose, alginate, and gelatin with the aid of glycerol as trihydric alcohol which participates in re-distribution of hydrogen bonds in the test system. FTIR, XRD, SEM, and TGA as instrumental techniques were used to structurally characterize the physical/chemical properties of the formed composite hydrogel. By using an exponential equation, swelling behavior of the hydrogel was evaluated. By incorporating a model drug (methylene blue—MB) in the formed hydrogel, experiments were directed to study release characteristics of the MB where the medium solution for the release was prepared at four different pHs. The maximum cumulative drug release at pH 2.8, 6, 7.4, and 9 were 42.8, 63, 80, and 84.5%, respectively. Data fitting process was carried out using five kinetic models (Korsmeyer-Peppas, Higuchi, Hopfenberg, zero-order, and first-order equations) and the preferred kinetic model at each pH was estimated by applying TOPSIS algorithmic technique. The adsorption capacity of the hydrogel in relation to MB was determined while thermodynamic properties of this relationship were quantified ($$\Delta{\text{H}}_{\text{ad}}^{0}= \text{ } -\text{99.95 kJ} \, {\text{mo}}{\text{l}}^{-{1}}$$ Δ H ad 0 = - 99.95 kJ mol - 1 and $$\Delta{\text{S}}_{\text{ad}}^{0}= -\text{0.237 kJ} \, {\text{mo}}{\text{l}}^{-{1}} {\text{K}}^{-{1}}$$ Δ S ad 0 = - 0.237 kJ mol - 1 K - 1 ). The results of the present study were in favor of the potential usage of the developed composite hydrogel in drug delivery systems.