This
work is strategically premeditated to study the potential
of a herbal medicinal product as a natural bioactive ingredient to
generate nanocellulose-based antibacterial architectures. In situ
fibrillation of purified cellulose was done in cinnamon extract (ciE) to obtain microfibrillated cellulose (MFC). To this
MFC suspension, carboxylated cellulose nanocrystals (cCNCs) were homogeneously
mixed and the viscous gel thus obtained was freeze-dried to obtain
lightweight and flexible composite aerogel architectures impregnated
with ciE, namely, ciMFC/cCNCs. At
an optimal concentration of 0.3 wt % cCNCs (i.e., for ciMFC/cCNCs_0.3), an improvement of around 106% in compressive strength
and 175% increment in modulus were achieved as compared to pristine
MFC architecture. The efficient loading and interaction of ciE components, specifically cinnamaldehyde, with MFC and
cCNCs resulted in developing competent antibacterial surfaces with
dense and uniform microstructures. Excellent and long-term antimicrobial
activity of the optimized architectures (ciMFC/cCNCs_0.3)
was confirmed through various antibacterial assays like the zone inhibition
method, bacterial growth observation at OD600, minimum
inhibitory concentration (MIC, here 1 mg/mL), minimum bactericidal
concentration (MBC, here 3–5 mg/mL), and Live/Dead BacLight
viability tests. The changes in the bacterial morphology with a disrupted
membrane were further confirmed through various imaging techniques
like confocal laser scanning microscopy, FESEM, AFM, and 3D digital
microscopy. The dry composite architecture showed the persuasive capability
of suppressing the growth of airborne bacteria, which in combination
with antibacterial efficiency in the wet state is considered as an
imperative aspect for a material to act as the novel biomaterial.
Furthermore, these architectures demonstrated excellent antibacterial
performance under real “in use” contamination prone
conditions. Hence, this work provides avenues for the application
of crude natural extracts in developing novel forms of advanced functional
biomaterials that can be used for assorted biological/healthcare applications
such as wound care and antimicrobial filtering units.