香港

Commercially available bandages such as hydrocolloid are neither biodegradable nor anti-bacterial. Chitin is known to be the second most naturally available polysaccharide which could be transformed to chitosan which is known to be anti-bacterial (Hasan, 2018) (Chao, 2019) and haemostatic (Okamoto, 2003) (Hu, 2018). Chitosan can be further converted to hydrogel which is bio-degradable and has good water absorbance. Anti-bacterial crab bio-bandages and crab bio-dressings should be bio-degradable as it took 42 days and a month for complete bio-degradation respectively, so they should be better than commercial bandages such as Nexcare Hydrocolloid as the disposal of anti-bacterial crab bio-bandages with bio-dressings would no longer pose burden to landfilling or threat to our environment. Anti-bacterial crab bio-bandages with bio-dressings are anti-bacterial with degree of deacetylation of DD% (measured using FTIR Spectrum II) 82.6% (due to the presence of chitosan) even without the application of other anti-bacterial agents and hence can provide complete protection of wounds from skin and soft tissues infections and haemostatic (due to the presence of chitosan). After testing and certification based on IS997:2004 and BS EN 13726-1, they should meet many requirements specified. Anti-bacterial crab bio-bandages should be eligible for marketing. Some results were as follows: 1.4 Anti-bacterial effect of crab hydrogels and roasted crab hydrogels Pure chitosan, crab chitosan, crab hydrogels and roasted crab hydrogels showed significant anti-bacterial effect. NO oral bacterial colonies were present in drinking water with crab hydrogels. Thus crab hydrogels could serve as effective anti-bacterial wound dressings. 1.6 Basing on IS997:2004 standard, the load per unit of area of anti-bacterial bio-bandages was 342g/m2 which met the minimum requirement of 36g/m2, the anti-bacterial bio-bandages had stronger tension strength (>20N both in dry and wet conditions) than commercial hydrocolloid. (2.7N dry 2.8N wet) which was comparable with that required (50-67N) and pH of about 7 which met the pH range of 4.5-8. 1.7 The FSA Free-Swell Absorbency of synthetic blood of crab hydrogel bio-dressings was 1.86g per 5cm x 5cm dressing which was much higher than that of commercial hydrocolloid (0.299g per 5cm x 5cm dressing) based on BS EN 13726-1.

The use of brine shrimp nauplii to test for the overall toxicity of sediment samples is proposed. Brine shrimp nauplii were cultured with different concentrations of heavy metals, including chromium (III), copper (II), nickel, lead and zinc, and organic pollutants, including triclosan, oxybenzone, octinoxate and bisphenol A. The brine shrimp nauplii were observed under a dissection microscope to determine the death rate. Results showed that brine shrimp nauplii are more sensitive to copper, cadmium, bisphenol A and oxybenzone. The LC50 (24h) are 55.5, 24.9, 5.6 and 2.7 ppm respectively. Zinc is likely to have synergistic toxic effect with nickel or lead. The synergistic toxic effects of other heavy metals and organic pollutants should be confirmed with further investigations. Brine shrimp nauplii were treated with extracts from sediment samples collected from the oyster culture zone of the Deep Bay, namely Pak Nei, Sha Kiu Tsuen and Hang Hau Tsuen. The sediment samples were extracted with neutral sodium acetate to dissolve the exchangeable heavy metal ions and some organic pollutants. The death rate of brine shrimp nauplii treated with the sediment extract of Hang Hau Tsuen was similar to 1 ppm PBA. It was also about 10 to 20% higher than that of the other two sites (Pak Nei and Sha Kiu Tsuen). Since Hang Hau Tsuen is closer to the residential area and Lau Fau Shan Seafood Market than the other two sites, its sediment sample is likely to have a higher level of environmental pollutants. The results suggest that brine shrimp nauplii may be used as a biomarker to monitor the environmental changes in the overall level of pollutants in sediment samples.

Commercially available bandages such as hydrocolloid are neither biodegradable nor anti-bacterial. Chitin is known to be the second most naturally available polysaccharide which could be transformed to chitosan which is known to be anti-bacterial (Hasan, 2018) (Chao, 2019) and haemostatic (Okamoto, 2003) (Hu, 2018). Chitosan can be further converted to hydrogel which is bio-degradable and has good water absorbance. Anti-bacterial crab bio-bandages and crab bio-dressings should be bio-degradable as it took 42 days and a month for complete bio-degradation respectively, so they should be better than commercial bandages such as Nexcare Hydrocolloid as the disposal of anti-bacterial crab bio-bandages with bio-dressings would no longer pose burden to landfilling or threat to our environment. Anti-bacterial crab bio-bandages with bio-dressings are anti-bacterial with degree of deacetylation of DD% (measured using FTIR Spectrum II) 82.6% (due to the presence of chitosan) even without the application of other anti-bacterial agents and hence can provide complete protection of wounds from skin and soft tissues infections and haemostatic (due to the presence of chitosan). After testing and certification based on IS997:2004 and BS EN 13726-1, they should meet many requirements specified. Anti-bacterial crab bio-bandages should be eligible for marketing. Some results were as follows: 1.4 Anti-bacterial effect of crab hydrogels and roasted crab hydrogels Pure chitosan, crab chitosan, crab hydrogels and roasted crab hydrogels showed significant anti-bacterial effect. NO oral bacterial colonies were present in drinking water with crab hydrogels. Thus crab hydrogels could serve as effective anti-bacterial wound dressings. 1.6 Basing on IS997:2004 standard, the load per unit of area of anti-bacterial bio-bandages was 342g/m2 which met the minimum requirement of 36g/m2, the anti-bacterial bio-bandages had stronger tension strength (>20N both in dry and wet conditions) than commercial hydrocolloid. (2.7N dry 2.8N wet) which was comparable with that required (50-67N) and pH of about 7 which met the pH range of 4.5-8. 1.7 The FSA Free-Swell Absorbency of synthetic blood of crab hydrogel bio-dressings was 1.86g per 5cm x 5cm dressing which was much higher than that of commercial hydrocolloid (0.299g per 5cm x 5cm dressing) based on BS EN 13726-1.

Formaldehyde is an air-borne, carcinogenic indoor pollutant. It may cause adverse effects on human health such as irritation of eyes and respiratory system. Shells of hermetia illucens, Black Soldier Flies (BSF) are leftovers when the insects mature from pupae to adults. BSF shells are rich in chitin which can be converted into chitosan by demineralisation and deacetylation. Chitosan and its ammonium salt (chitogel) can remove formaldehyde via condensation of water. In this investigation, the efficiency of removal of formaldehyde by different substrates were compared including shells of BSF before and after demineralization, deacetylation and action of vinegar; and common commercial products and Anti-Forma Chitogels made from shells of BSF and some crustaceans. Anti-Forma Chitogel of BSF was found to be effective in removing (91.2%) formaldehyde (1:20 by mass) among shells of BSF with different treatments and its efficiency was better than all commercial products tested. Concentration of formaldehyde in the container with deacetylated Anti-Forma Chitogel is 0.54 mg/m3. It removed 74.8% of formaldehyde compared to the control (2.14 mg/m3). Concentration of formaldehyde in the container with Anti-Forma Chitogel without deacetylation is 0.76 mg/m3 . It removed 64.5% of formaldehyde compared to the control (2.14 mg/m3). The Anti-forma Chitogel of BSF was found to be eco-friendly with high formaldehyde removal efficiency when placed in a drawer (removal of 54.8% of in 24 hours), the chamber of a newly renovated room (removal of 84.9% in 30 minutes reducing the conc. of formaldehyde from 0.53 mg/m3 to 0.08 mg/m3; cf. the safety limit of formaldehyde <0.125mg/m3) and drawers of a new wardrobe (removal of 83.7% at 20.2oC in 1 day reducing the conc. of formaldehyde from 0.49 mg/m3 to 0.08 mg/m3 & kept the conc. of drawers below 0.125mg/m3 most of the time over a month when temperature was below 21oC). Conc. of formaldehyde in air-tight boxes (5g of construction adhesive in 9.3 dm3) with air purifiers with and without Anti-forma Chitogel as filter before and after 3 hours was reduced by 44.5% (from 6.25mg/m3 to 3.47mg/m3 ) and 27.7% respectively showing that Anti-forma Chitogel as filter in air purifier outperformed that without by 160%. Besides, anti-forma Chitogel is antibacterial, so it would also kill bacteria when used in air purifiers. [1] proving that Anti-forma Chitogel is effective in removal of formaldehyde on the spot and can be applied to households. It can also help achieve Target 3.9 and 12.5 of the Sustainable Development Goals of the United Nations.

Upcycling abandoned beehives to make new products can reuse the useful materials in old beehives and produce less trash. As known that bees leave their beehive in these following situations like insufficient replenishment, frequent unboxing and environmental issues. Then the beehive will be abandoned and will have no use left. In this project, a piece of honeycomb was collected from abandoned beehive and melted in order to extract beeswax. The potential of the extracted beeswax for replacing plastic to produce fillers of 3D pens was studied. Natural materials like seashell, rosin, soy bean and coffee ground were tested as ingredients of 3D printing materials. Finally, the potential of using extracted beeswax in 3D printing was confirmed. Beeswax has a low melting point at around 64°C and solidify quickly at room temperature. The high plasticity of this natural wax fulfills the criteria of 3D printing materials. Biodegradable wastes, like coffee grounds and soy bean grounds were tested as additives for reducing the beeswax content. Sea shell grounds were eliminated from the tested list as its filaments broke into small pieces of brittle fragments during the production process. 5% and 10% of these additives were the optimal formula for making long filaments. Yet, the thin filaments made by pure beeswax were not strong enough, filaments of selected beeswax-soy bean grounds were further strengthened by mixing with 5% or 10% rosin. Among the four different ratios of Beeswax: Soy bean grounds: Rosin (9:1:0.5 / 9:1:1 / 9.5:0.5:0.5 / 9.5:0.5:1), filaments in the ratio 9.5:0.5:0.5 demonstrated better flexibility, higher tensile strength and compressive strength, thus B9.5:S0.5:R0.5 was the final formula of biodegradable beeswax 3D filament.

In the first part of this project, distilled water and 95% ethanol were used to extract ultra-violet(UV)-absorbing and anti-oxidizing compounds from different types of algae including kelp, wakame, sea grape and nori. Activated charcoal was used in attempt to purify the extracts and removed excessive pigments. It was found that the charcoal was more effective in adsorbing pigments from ethanol extract in which up to 80 to 100% pigments could be removed. The UV-absorbing and anti-oxidizing properties of the algae extracts were also studied. All algae extracts showed significant UV-absorbing and anti-oxidizing properties. In particular, extract formed by using 3 g kelp powder in distilled water could significantly reduce 50% UV intensity and react 96.5% DPPH solution which acts as a source of free radicals. In the second part of the project, three applications of algae were explored in details. Firstly, it was found that kelp, wakame and nori extracts by using over 2 g of algae in 30 mL olive oil could absorb UVA and UVB by over 90%, which is comparable to the performance of zinc oxide, a common ingredient in commercial sunscreen products. Costs of preparing the sunscreens were also compared. Except for wakame extract, all other extracts were cheaper than using zinc oxide. Moreover, the kelp extract was found to maintain its UV- absorbing and anti-oxidizing abilities after at least 30 days of storage under room conditions. Lastly, sodium alginate was successfully extracted from kelp with a product yield up to 30%. The alginate solution was then used to form a calcium-alginate protective coating on plastic slides to reduce UV intensity by up to 50%. This aims to apply on nails or fingers during UV nail gel polish to protect against UVR.