This paper presents an extension of Specular Bit Architecture (SBA) (DOI: 10.5281/zenodo.18980986) that frames SBA as a practical encoding and local‑repair primitive for biological microchips and DNA data storage. Building on the original SBA formalism, we (i) adapt the two‑bit specular cell model to substrate‑aware physical constraints, (ii) formalize a conservative sanitization operator with explicit compensating actions, (iii) prove a strengthened bounded‑propagation theorem under synchronous read‑then‑write semantics and canonical input assumptions, and (iv) provide an exhaustive enumeration methodology and reproducible scripts for verifying local repair behavior in width‑5 windows. The resulting encoding combines Fibonacci‑weighted positional semantics with a specular two‑bit physical layout to deliver a robust, locality‑preserving mapping from logical digits to substrate states. We emphasize practical implications: SBA’s locality and bounded‑round repair properties reduce long‑range error propagation, making it suitable for wetware microchips, enzymatic or polymer‑based logic layers, and high‑density DNA storage systems where local sanitization and minimal propagation are critical. The contribution is theoretical and reproducible: we include formal proofs, the corrected sanitization semantics, and supplementary enumeration code to enable experimental validation on biological and hybrid microelectronic platforms. Keywords Specular Bit Architecture; DNA storage; biological microchips; Fibonacci‑weighted encoding; sanitization; bounded propagation; canonical representation; local repair.