The practice of combining external stimulation therapy alongside stimuli-responsive bio-scaffolds has shown massive potential for tissue engineering applications. One promising example is the combination of electrical stimulation (ES) and electroactive scaffolds because ES could enhance cell adhesion and proliferation as well as modulating cellular specialization. Even though electroactive scaffolds have the potential to revolutionize the field of tissue engineering due to their ability to distribute ES directly to the target tissues, the development of effective electroactive scaffolds with specific properties remains a major issue in their practical uses. Conductive polymers (CPs) offer ease of modification that allows for tailoring the scaffold’s various properties, making them an attractive option for conductive component in electroactive scaffolds. This review provides an up-to-date narrative of the progress of CPs-based electroactive scaffolds and the challenge of their use in various tissue engineering applications from biomaterials perspectives. The general issues with CP-based scaffolds relevant to its application as electroactive scaffolds were discussed, followed by a more specific discussion in their applications for specific tissues, including bone, nerve, skin, skeletal muscle and cardiac muscle scaffolds. Furthermore, this review also highlighted the importance of the manufacturing process relative to the scaffold’s performance, with particular emphasis on additive manufacturing, and various strategies to overcome the CPs’ limitations in the development of electroactive scaffolds.

In this work, Cr-ZrO2 composite coating were prepared by electrodeposition method on aluminium substrate from chromic acid based electrolytes containing gelatin. The effect of gelatin on the corrosion resistance of Cr-ZrO2 coatings were studied in 3 wt.% sodium chloride solutions. Potentiodynamic polarization studies were performed using a Versastat 3 (Princeton Applied Research) electrochemical system with a three-electrode cell. Results shows that the corrosion resistance of Cr-ZrO2 coating on Al substrate was improved by the addition of gelatin to the coating solution. The addition of gelatin shifted the potentiodynamic polarization curved in the noble direction. The corrosion potential changed positively from -778 mV to -259 mV. The corrosion rate of Cr-ZrO2 coating decreased from 4.44±0.93 mpy to 0.13±0.01 mpy with the addition of 3g/L gelatin.

The development of potential alternative binders to Portland cement is still becoming a global challenge in housing and infrastructure aspects. That is because cement and concrete become the major materials needed in building constructions. The Ordinary Portland cement can form a solid and hard mass when mixed with water with a certain ratio. This is due to the formation of ettringite and calcium silicate hydrate (CSH) phases that contribute to the strength of the hydrated products about 33–53 MPa. However, the manufacturing temperature of Portland cement can reach up to 1,500 °C in producing clinker. In order to lower the energy consumption and production cost, scientists were trying to utilize pozzolanic materials. The research of pozzolanic materials as alkali-activated cement, such as soil cement or geopolymer cement, is also still conducted. Hence, a better understanding of pozzolanic reaction and its hydration products is needed. In this work, the hydration products of low-energy binders composed of Ca(OH)2-SiO2 and Ca(OH)2-metakaolin-gypsum mixtures were studied. The hydrated products of 41 wt. % Ca(OH)2 – 41 wt. % metakaolin – 18 wt. % gypsum mixtures followed by water immersion curing at 50 °C for 28 days undergone a pozzolanic reaction. XRD characterization showed that the hydrated product is mainly composed of ettringite (60.0 %) and crystalline-CSH (23.4 %). The diffractograms obtained have shown a specific hump indicating the presence of amorphous phases besides the crystalline. To confirm the presence of the non-crystalline or amorphous phases of the hydrated products, a polarizing optical microscope (OM) using a crossed Nicols method was used. The characterization of the phases is the novelty of the present research. The ettringite, crystalline CSH and the amorphous phases act as a strong binder that consequently contribute to its average maximum compressive strength of 22.17 MPa.

Studies on hydroxyapatite are plentiful since the compounds are alike to the bone and sometimes combined with Zn to fabricate a longstanding structure and improve cell regeneration. However, construct a 3D model of HAp-Zn through sintering required high energy. Therefore, this study performed a low-temperature process using alginate, taking a role as a matrix, to achieve an interconnected porous structure while maintaining mechanical properties. The variations of alginate concentrations (0%, 2%, 4%, and 6%) were mixed with HAp-Zn powder using PBS and CaCl2. The bone scaffold was then characterized using XRD, FTIR, SEM, and compressive test. The XRD result showed that alginate addition did not change the HAp-Zn structure and phase. The degree of crystallinity and crystallite size was found to decrease with the increasing composition of alginate. The FTIR spectra also displayed an intermolecular interaction between HAp-Zn and SA. On the other hand, the SEM observation contained well interconnectivity with 50-200 μm of pore size. It led to an incline in ultimate compressive strength and modulus of elasticity with the uppermost value was 2.05 ± 0.06 MPa and 0.037 ± 0.001 GPa respectively in 6% of alginate.

Various species of Bamboo is widely available in Indonesia. Usually it is used as pillars, roof frame, and for walls in a woven form and it can be used for steel substitute in reinforced concrete. In making bamboo as a strengtheners or reinforcement a proper volume fraction should be chosen. Besides that, the minimum distance between bamboo bars or inter-strengtheners distance must be determined so that the reinforcement effect on cement matrix takes place. Ten variations of mixtures were used in this research. The number and distance between reinforce bars and its arrangement perpendicular or parallel with loading direction. From the observation it is found that both of the vertically and horizontally arranged bamboo bars at minimum inter-strengtheners distance of 10 mm gave maximum reinforcement and the flexural strength are 16.1 ± 0.3 MPa and 15.8 ± 0.6 MPa. Whereas cement only sample gave 7.2 ± 0.6 MPa hence 2 folds increase. For distance less than 10 mm, the flexural strength is lower, even volume fraction is relatively high and it supposed to give higher strength, in fact this is due to composite reinforcement effect did not occur and this is belief due to a hindered hydration process.