Biodegradable Substrate Research Articles

Conjugated polymer‐reinforced cellulosic frameworks: a promising approach for flexible electronics

AbstractFlexible electronics are seamlessly integrated into our lives, from foldable displays to smart wearables, redefining our interaction with technology. The use of metals and semiconductors in these flexible devices is limited due to their poor bendability and stretchability. Consequently, integrating conjugated polymers (CPs) into a cellulosic framework has emerged as a promising approach for advancing flexible electronics. Cellulose, as an abundant and sustainable biopolymer, offers a compelling solution to the escalating global e‐waste crisis by providing a cost‐effective and biodegradable substrate. This synergy has the potential to address environmental concerns and unlock new avenues of flexible, eco‐friendly and sustainable electronic devices. Herein the unique properties and synthesis routes of CPs are briefly introduced including their opportunities and challenges. The review discusses a facile and efficient approach to circumvent the challenges of CPs using cellulose as a substrate. The review explores fabrication approaches of CP–cellulose composites aimed at enhancing mechanical, electrical and optical properties. Through a critical examination of recent studies and advancements, it highlights how CPs reinforce the cellulose framework and investigates their structure–property relationships, which are crucial for tailoring the properties for desired applications. Finally, the review presents an outlook on potential challenges and prospects for advancing CP‐based cellulose composites in flexible electronics. © 2025 Society of Chemical Industry.

Investigating enhancement of protease and lysozyme combination pretreatment on hydrolysis of sludge organics under humic acid inhibition

This study investigated the impact of humic acid (HA) on enzymatic pretreatment efficiency, focusing on sludge properties and HA molecular structure. The results showed that enzymatic pretreatment alleviates HA inhibition, improving hydrolysis efficiency. In the presence of HA, soluble proteins and polysaccharides in the enzyme-cocktail group reached 27.7 mg/L and 23.9 mg/L, 1.4 and 1.3 times higher than the blank group, respectively. The enzyme-cocktail group also had the highest soluble DNA concentration (19.4 mg/L) and the lowest viable cell proportion (69.3 %), indicating effective cell lysis. Enzyme-cocktail pretreatment reduced electrostatic repulsion, enhancing the mobility of extracellular organics. Enzyme interactions with HA released internal hydrolases and decreased amide groups on the HA surface, increasing the availability of biodegradable substrates. Overall, enzymatic pretreatment proves effective in mitigating HA-induced inhibition, thereby improving sludge biodegradation and enhancing carbon recovery in anaerobic fermentation.

Enhancing dark fermentative biohydrogen and VFA production via ozone pre-treatment.

This study investigates the effects of ozone pre-treatment on two types of organic wastes: secondary sludge (SS) and wine vinasse (WV). Ozone pre-treatment of SS, a semi-solid waste, significantly increased the Dissolved Organic Carbon (DOC) and Total Volatile Fatty Acids (TVFAs) through hydrolysis. Conversely, ozone pre-treatment of WV, a liquid organic waste, reduced the availability of soluble biodegradable substrates and decreased the concentration of carboxylic acids with carbon chain length higher than 4. Based on these findings, the impact of ozonation on subsequent dark fermentation Biochemical Hydrogen Potential (BHP) was assessed for SS. The results, modeled for an ozone dose of 0.018 g O3/g TS, indicated a substantial enhancement in bio-hydrogen production by approximately 160% and VFA production by about 350%. In conclusion, ozone pre-treatment shows significant potential to enhance dark fermentation of particulate substrates like secondary sludge, supporting sustainable waste valorization strategies.

Bio-Inspired Eco-Composite Materials Seaweed Waste Integration for Sustainable Structural Applications

The increasing levels of atmospheric carbon dioxide (CO2) and plastic waste in marine environments demand immediate action to mitigate their effects. A promising solution lies in enhancing algal cultivation in marine environments, which not only absorbs CO2 and produces oxygen (O2) but also contributes to carbon sequestration. This study aims to develop biodegradable substrates for algae cultivation, facilitating their gradual degradation in marine environments and eventual deposition on the ocean floor, thereby addressing both plastic pollution and CO2 emissions. We selected various degradable polymers and incorporated differing proportions of algae residue powder (10%, 20%, and 30% by weight) into these substrates. The compositions were processed through extrusion and molded into test samples for hot compression molding. Characterization included assessments of mass loss, morphology, chemical composition, and mechanical strength under both dry conditions and after immersion in seawater for up to two months. The results indicate that the incorporation of algae residue significantly accelerates the degradation of the samples, particularly under extended exposure to seawater. Mass loss measurements indicated that samples with a 30 wt% algae addition experienced mass losses of up to 12% after two months of immersion. Mechanical strength tests demonstrated a reduction of up to 57% in strength due to the incorporation of algae, with seawater immersion further exacerbating this loss. These findings highlight the potential of biopolymer substrates infused with algae residue for effective carbon sequestration through enhanced algae cultivation.

Comparative performance investigation of rectangular microstrip antennas utilizing polydimethylsiloxane (PDMSCNT) and polycaprolactone (PCL-CNT) composites at 2.4 GHz and 5.8 GHz

ABSTRACT Current research efforts are directed towards utilizing polymers and biodegradable materials to develop innovative wireless devices for emerging applications within the sub-6 GHz spectrum. This study seeks to enhance the electrical and radiation characteristics of antennas while ensuring favorable environmental properties such as flexibility and Specific Absorption Rate (SAR). To this end, a comparative analysis of two flexible rectangular microstrip antennas constructed from novel polymer-based substrates is presented. One antenna uses a flexible composite substrate of polydimethylsiloxane (PDMS) embedded with carbon nanotubes (CNT), while the other employs a biodegradable polymer composite substrate made of polycaprolactone (PCL) reinforced with CNT. Results indicate that the PCL-CNT antenna surpasses the PDMS-CNT antenna in performance, in both flat and bent conditions. Specifically, at 2.4 GHz, the PCL-CNT antenna achieved a gain of 4.46 dBi and an efficiency of 0.70, compared to a gain of 3.94 dBi and an efficiency of 0.61 for the PDMS-CNT antenna. Furthermore, the superior performance of the PCL-CNT biodegradable polymer composite antenna suggests its potential for IoT applications and wireless communications, combining effective on-body usage with minimal environmental impact.

A high-rate A2O bioreactor with airlift-driven circulation and anoxic hybrid growth for enhanced carbon and nutrient removal from a nutrient rich wastewater.

Within this research, a one-stage hybrid dual internal circulation airlift A2O (DCAL-A2O) bioreactor was designed and operated to simultaneously remove carbon, nitrogen and phosphorous (CNP) from milk processing wastewater (MPW) in different operational circumstances. The substantial operating variables monitored in this work were including hydraulic retention time (HRT), airflow rate (AFR) and aeration volume ratio (AVR) ranged from 7 to 15h, 1-3L/min and 0.324-0.464, respectively. From the view point of economics and process function, the optimum conditions were obtained at the HRT, AFR and AVR of 10h, 2L/min and 0.464, respectively. At the optimum conditions TCOD, TN, TP removal efficiencies and effluent turbidity were reported to be 97 %, 90 %, 92 % and 9 NTU, respectively. The impact of wastewater biodegradability (BOD5/COD) was evaluated on the bioreactor performance using two other wastewaters i.e. soft drink (SDW) and soybean oil plant wastewaters (SOW) in comparison with the MPW. Removal efficiencies for TCOD and TN exceeding 80 % were observed. The feeding location revealed a prominent impact on the TN and phosphorous removal efficiencies (both ≥80 %) related to the availability degree of the readily biodegradable organic substrate to denitrifiers and PAOs. The rise in HRT, AFR and AVR resulted in reducing microbial secretions as SMP present in sludge and bioreactor effluent as well as loosely bounded EPS (LB-EPS), reported to be 26, 28, 32.5 and 194.4mg/L TOC, respectively. Different bacteria species were present at optimum conditions confirming concurrent CNP removal in a single body. Finally, the operating cost evaluation verified the effectiveness of the hybrid airlift A2O treating the MPW.

Development of Biodegradable Substrates and Synaptic Transistors for Next‐Generation Transient Electronics

AbstractUbiquitous electronic gadgets in lives have led to an increase in electronic waste (e‐waste), posing a threat to the environment and ecology that must be addressed. This work demonstrates the use of gelatin, a natural protein, for development of flexible biodegradable substrates and synaptic transistors using the same material as gate dielectric. The fabricated p‐channel transistors exhibit high electrical stability and exceptional synaptic characteristics through spike timing dependent plasticity (STDP), spike voltage dependent plasticity (SVDP), and spike number dependent plasticity (SNDP), respectively upon variation of post‐synaptic current (PSC) with time, amplitude, and number of stimuli. These devices exhibit pulse paired facilitation (PPF) with relaxation time constants in the range of ≈10 ms and regulating modulation amplitude of 1 greatly resembling a biological synapse. Study on the variability among distinct devices and over multiple cycles demonstrate outstanding repeatability of synaptic plasticity. The devices showcase significant PSC values with almost linear SNDP, while consuming an ultralow power of ≈11.7 fJ. Excellent stability is observed when subjected to multiple bending sequences. Complete dissolution of these devices in aqueous environments in an hour without any alteration to temperature or pH confirms excellent biodegradability of these devices leading toward transient neuromorphic circuits and systems that adhere to the concepts of circular economy.

Development of an Electrowetting-on-Dielectric Cellulose-Based Conductive Sensor Using Direct Inkjet Printed Silver Nanoparticles

In the quest for sustainable and efficient solutions for modern electronics, flexible electronic devices have garnered global attention due to their potential to revolutionize various technological applications. The manufacturing of these devices poses significant challenges, particularly regarding environmental sustainability and ease of production. A novel method employing direct inkjet printing of silver nanoparticle (npAg) ink onto cellulose nanocrystal (CNC) substrates is presented, offering a promising alternative to conventional methods. This study demonstrates the ability of CNCs to serve as a flexible and biodegradable substrate that does not require complex post-printing treatments to achieve adequate electrical performance. This method was implemented in the fabrication of an electrowetting-on-dielectric (EWOD) device, achieving circuit patterns with high resolutions and reduced resistances. The findings not only validate the use of CNCs in flexible electronic applications but also underscore the potential of advanced printing techniques to develop flexible electronics that are environmentally sustainable and technically feasible.

Humidity-induced self-powered photodetection through Bi2Te3/MoS2 nanohybrid material deposited on a flexible substrate

Harvesting energy from humidity is an environmentally friendly technology. In arid regions, instead of negative impact of humidity, it is also feasible to capture water from the air, making our device suitable without the need for any external power supply. Self-powered photodetectors are in high demand due to their zero power consumption and suitability for wearable electronics. Herein, we have incorporated Bi2Te3 nanosheets with MoS2 on a flexible and biodegradable cellulose paper substrate to create the device. According to XPS analysis, Bi 4F7/2 and Bi 4F5/2 levels were identified at binding energies of 157.62 eV and 162.90 eV, respectively indicating double splitting of the Bi atoms. In such a novel Bi2Te3/MoS2 nanohybrid photodetector, rapid electron transfer at Bi2Te3 and MoS2 interface occurs due to humidity, significantly enhancing performance of the photodetectors in the UV spectral range. This performance is better as compared to conventional MoS2-based photodetector, exploiting the unique properties of topological insulator Bi2Te3. The device demonstrated the highest responsivity of 19.1 A/W and detectivity of 7.81 × 1011 Jones, exhibiting significant responsivity of 3.74 mA/W and detectivity of 9.59 × 109 Jones even at 0 V with minimum optical signal of 68.9 μW/cm2. It also offers the highest external quantum efficiency of 6471.29 %.

Sustainable Lithography Paradigm Enabled by Mechanically Peelable Resists.

Lithography is critical in micro- and nanofabrication processes, enabling the development of integrated circuits, semiconductor devices, and various advanced electronic and photonic systems. However, there are challenges related to sustainability, efficiency, and yield, as well as compatibility with transient electronics. This work introduces a sustainable lithography paradigm employing mechanically peelable resists compatible with existing cleanroom processes. The resists exhibit near-zero adhesion to various substrates, facilitating efficient, cost-effective, environmentally friendly, and chemical-free mechanical stripping without observable particulate residues. The mechanical lift-off process enables scalable and 100%-yield pattern transfer using commercially available tape within seconds. Furthermore, the new paradigm supports distributed and in situ conformal manufacturing using the peelable resist as a "transferable stencil mask" to fabricate various functional devices on flexible and nonplanar surfaces, as well as ultra-thin biodegradable substrates. Overall, this work expands the potential for using lift-off as a standard process in the pan-semiconductor industry and opens new avenues for lithographic procedures aimed at the reliable mass production of transient electronics and integrated biodegradable devices, addressing growing sustainability issues caused by electronic waste.

Comparing the yield of potato starch-based bioplastics extracted using various pH media

For the environment and biodiversity, the accumulation of petroleum-based plastics and their slow biodegradability provide a host of difficulties. This study is concerned with creating plastic-based starch to identify a replacement for this common material. Since the potato is the primary naturally occurring biological and biodegradable substance, different media (neutral, alkaline, and acidic) were used to extract the starch for soaking. Based on the comparison of the starch extraction yields from the three media to determine the yield of bioplastic from each, it was found that the production of bioplastics is most effective in a neutral medium. In contrast, acidic and alkaline media provide lower yields. This study also looks into the possibility of using gorgeous potato peels, an industrial food waste product, to make bioplastics. In addition to highlighting ecologically friendly alternatives to conventional plastics, it also emphasizes the significance of pH in the extraction of starch and its subsequent usage in creating bioplastics. It also supports ongoing efforts to reduce plastic waste and pollution.

Lake Shore Restoration with Vallisneria spiralis in Lake Como (Northern Italy) to Improve Sustainability

In the Anthropocene era, lake ecosystems are increasingly subjected to significant human-induced pressures, leading to declines in both biodiversity and habitat quality. However, restoration initiatives offer promising avenues for enhancing the resilience of freshwater environments. This research investigated a range of established and novel methods aimed at promoting the growth of the macrophyte Vallisneria spiralis in the littoral zone of Lake Como, a southern alpine lake in Italy. To conduct this study, samples of Vallisneria spiralis were collected and placed in tanks containing four different types of 3D-printed biodegradable substrates. The optimal conditions for the growth of this species were identified as follows: a temperature range of 25 to 27 °C, the continuous operation of a circulation pump equipped with a filter, the presence of a fertile substrate, and light cycles comprising 6 h of peak illumination followed by 6 h of darkness. Remarkably, the plants exhibited a growth rate of 4 mm per day, increasing from an initial count of 12 specimens to 400 within four months, with a total of over 700 plants by the end of the study. Among the substrates tested, the patch substrate was found to be the most effective. After their introduction into the natural environment, the survival rate of plants established on stable substrates in contact with the lakebed reached an impressive 85.7%. This research represents a pioneering step in demonstrating that Vallisneria spiralis may serve as a viable option for restoration projects in coastal lake habitats, particularly when employing biodegradable substrates.

In Vivo Study of Organ and Tissue Stability According to the Types of Bioresorbable Bone Screws.

Biodegradable material, such as magnesium alloy or polylactic acid (PLA), is a promising candidate for orthopedic surgery. The alloying of metals and the addition of rare earths to increase mechanical strength are still questionable in terms of biosafety as absorbent materials. Therefore, the purpose of this study is to understand the effect of substances due to the degradation of various biodegradable substances on organs in the body or surrounding tissues. A total of eighty male Sprague-Dawley rats were selected for this study, and the animals were divided into four groups. Each of the three experimental groups was implanted with magnesium alloy, polymer, and titanium implants; the control group only drilled into the cortical bone. Serum assay, micro-CT, hematoxylin and eosin staining, immunoblotting, and real-time PCR were evaluated. There was no significant difference between the two groups of magnesium alloy and polymer in serum assay, but micro-CT analysis confirmed that magnesium alloy degrades faster than polymer, and histological examination showed a strong inflammatory response in the early stages, which was similarly observed in immunoblotting and real-time PCR. Our findings show that there was no toxicity due to the degradation of the biodegradable material, and the difference in each inflammatory response is thought to be determined by the rate of degradation in the body.

MXene/Bacterial Cellulose Hybrid Materials for Sustainable Soft Electronics.

This work evaluated bacterial cellulose (BC) as a possible biodegradable soft electronics substrate in comparison to polyethylene terephthalate (PET), while also focusing on evaluating hybrid MXene/BC material as potential flexible electronic sensor. Material characterization studies revealed that the BC material structure consists of nanofibers with diameters ranging from 70 to 140 nm, stacked layer-by-layer. BC samples produced are sensitive to post-treatment with isopropanol resulting in a change of structural and mechanical properties. The viscoelastic properties of the BC substrates have been studied experimentally in comparison with the PET film. Aged BC substrate showcased similar viscoelastic properties stability, while exhibiting better properties above 70 °C, with total storage modulus change of -15% and loss modulus change of 21%. MXenes prepared using the Minimally Intensive Layer Delamination (MILD) method were screen-printed onto BC substrates and PET films to form MXene/BC (MX/BC) and MXene/PET (MX/PET) devices. The electrical properties results showcased different resistive behavior on both BC and PET substrate samples with different impedance moduli. MX/PET presented lower sheet resistance of around 156 Ω·sq-1, while MX/BC was 2733 Ω·sq-1. Finally, the MX/BC and MX/PET devices were subjected to repeatable quasi-static load tests and the piezoresistive sensing behavior of the devices has been reported.

Indigenous bio-coagulant assisted electrocoagulation process for the removal of contaminants from brewery wastewater: Performance evaluation and response surface methodology optimization

Wastewater from human activities, particularly from brewery industries, is a significant source of pollution. Large volumes of biodegradable and non-biodegradable substances found in brewery effluent make them suitable for natural coagulant-assisted electrocoagulation. The treatment options available today are highly harmful and not economical. To solve this problem and provide a simple method of treating brewery wastewater, the biocoagulant (Custard apple)-assisted electrocoagulation process was created. This study presents an environmentally friendly way of treating wastewater by combining electrocoagulation with biocoagulant. The approach treats wastewater from breweries with a high organic load and a variable composition. Bio- and electrocoagulation are used in the process to target certain contaminants and when combined the method has high efficiency and is environmentally also friendly. The performance of bio-coagulant-assisted electrocoagulation was studied, considering parameters such as pH, time, current, and bio-coagulant dosage. In each experiment, operating parameters were adjusted and their removal efficiency was evaluated after treatment. The bio-coagulant-assisted electrocoagulation process removed COD (99.01 %), BOD (99.09 %), TDS (99.02 %), and) at an ideal pH of 7, a current of 0.5 A, a time of 40 min, and power consumed (0.54kwh/m3) with a constant dose of 0.75 g/l NaCl as electrolytes. The study found that Indigenous bio-coagulant (Custard apple)-assisted electrocoagulation processes were effective and efficient in removing pollutants from brewery wastewater. In the process of treatment operating factors have a high effect on the performance of the method. The parameters were customized using Response Surface Methodology (RSM), and the dependent variable's value was determined through regression analysis with a design expert.

Biodegradable Substrates for Rigid and Flexible Circuit Boards: A Review

Biodegradable Substrates for Rigid and Flexible Circuit Boards: A Review

Corrosion and scaling inhibition effects of Passiflora edulis Sims peel extract in simulated circulating cooling water: Experimental and theoretical insights

Passiflora edulis Sims peel extract (PESPE) is a biodegradable substance derived from agricultural waste. In this study, we tested PESPE as a corrosion and scale inhibitor in simulated circulating cooling water (SCCW) and its effect on CaCO3 scale formation via static scale inhibition. The chemical composition and microstructure of CaCO3 scale were analyzed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM). The ability of PESPE to inhibit the corrosion of mild steel (MS) in SCCW was investigated via electrochemical tests and microscopic analyses. PESPE exhibited excellent performance in inhibiting both CaCO3 scale formation and MS corrosion, with inhibition efficiencies of 93.5 % and 85.0 %, respectively. PESPE converted the stable CaCO3 deposits into unstable, flocculent, and fine particles, decreasing their size from 57 to 2 μm. Furthermore, it acted as an anode-type corrosion inhibitor for MS, with its corrosion inhibition efficiency being positively correlated with its concentration. The active components of PESPE adsorb onto the MS surface to form a protective film; the synergistic adsorption behavior of the active components was confirmed via density functional theory (DFT) and molecular dynamics (MD) simulations. Our findings prove that PESPE is a sustainable alternative to conventional chemical inhibitors.

Convert food waste into easily biodegradable liquid substrate: New insights into wet oxidation as a pretreatment for anaerobic digestion

This study is the first comprehensive investigation into the industrial application of wet oxidation (WO) for food waste (FW) valorization. We analyzed the physicochemical properties of WO products and performed a material flow analysis. WO achieved a 25.7 % reduction in chemical oxygen demand and produced liquid and solid products suitable for high-value applications. The liquid product featured high biodegradability (B/C ratio of 0.65), significant BOD5 (33 ± 9 g/L), low total solids (3.5 % ± 0.4 %), and low metal concentrations, making it ideal for high-efficiency anaerobic digestion or as a carbon source in wastewater treatment. The solid product, with a total solids content of 63.9 % ± 1.4 %, is a potential organic fertilizer alternative. Life cycle assessment showed that WO-related scenarios offered superior greenhouse gas (GHG) reduction compared to conventional anaerobic digestion (11.30 kg CO2-eq/t FW slurry). The most effective scenario, combining WO with a carbon source and organic fertilizer alternative, achieved a GHG reduction of −21.80 kg CO2-eq/t FW slurry. Consequently, this study demonstrates that WO, as a pretreatment for food waste valorization, is both technically feasible and environmentally sound, offering valuable engineering references for the implementation of high-efficiency anaerobic digestion processes for food waste.

Early-stage breast cancer screening using a new biodegradable and easily implantable multi-element sensor in sub-THz range

In this article, a new biodegradable and easily implantable multi-element sensor is presented for early-stage breast cancer screening within the Sub-THz frequency range. The evolution of the sensor begins with the development of a single element. Once the desired operating frequency of operation is accomplished by the single element it is transformed into a multi-element configuration. The sensor is implemented on a compact size (20,000 × 20,000 µm2) easily biodegradable cordura substrate. The sensor performance is evaluated in terms of in-band reflection, directivity and surface current. The sensor is offered Factional Bandwidth (FBW), average directivity and surface current density 115.15%, 10.5 dBi and 20 A/m, respectively. The breast phantom screening is carried out for normal and malignant phantoms of (Tis, N0, M0), (T1, N0, M0) and (T2, N1, M0) using the proposed Multi-Element Sensor (MES). The Principal Component Analysis (PCA) results, error bar and sensitivity parameters are accounted for in the analysis to discriminate the normal phantom from malignant phantoms. The sub-THz range of operation of the proposed sensor has opened a new research scope for medical screening applications and the proposed method comparatively, offers a wide range of measurements for tumour detection.

Engineering Triphasic Nanocomposite Coatings on Pretreated Mg Substrates for Biomedical Applications.

Biodegradable polymer-based nanocomposite coatings provide multiple advantages to modulate the corrosion resistance and cytocompatibility of magnesium (Mg) alloys for biomedical applications. Biodegradable poly(glycerol sebacate) (PGS) is a promising candidate used for medical implant applications. In this study, we synthesized a new PGS nanocomposite system consisting of hydroxyapatite (HA) and magnesium oxide (MgO) nanoparticles and developed a spray coating process to produce the PGS nanocomposite layer on pretreated Mg substrates, which improved the coating adhesion at the interface and their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs). Prior to the spray coating process of polymer-based nanocomposites, the Mg substrates were pretreated in alkaline solutions to enhance the interfacial adhesion strength of the polymer-based nanocomposite coatings. The addition of HA and MgO nanoparticles (nHA and nMgO) to the PGS matrix, as well as the alkaline pretreatment of the Mg substrates, significantly enhanced the interfacial adhesion strength when compared with the PGS coating on the nontreated Mg control. The average BMSC adhesion densities were higher on the PGS/nHA/nMgO coated Mg than the noncoated Mg controls under direct contact conditions. Moreover, the addition of nHA and nMgO to the PGS matrix and coating the nanocomposite onto Mg substrates increased the average BMSC adhesion density when compared with the PGS/nHA/nMgO coated titanium (Ti) and PGS coated Mg controls under direct contact. Therefore, the spray coating process of PGS/nHA/nMgO nanocomposites on Mg substrates or other biodegradable metal substrates could provide a promising surface treatment strategy for biodegradable implant applications.